The invention relates to an apparatus having a mains cable and having a housing lead-through through which the mains cable is passed, and having a cable grommet in the area of the housing lead-through, through which cable grommet the mains cable is passed. The cable grommet has a first grommet portion and a second grommet portion, of which two grommet portions the first grommet portion is attached to the housing in the area of the housing lead-through and is designed to have a comparatively low flexibility relative to the second grommet portion. The second grommet portion extends from the first grommet portion up to the free end of the cable grommet and is designed to have a comparatively high flexibility relative to the first grommet portion and is formed with grommet apertures in order to achieve the comparatively high flexibility, which grommet apertures are arranged after one another in a grommet direction which extends from the first grommet portion to the second grommet portion.
The invention further relates to a cable grommet having a first grommet portion and a second grommet portion, of which two grommet portions the first grommet portion is designed to be attached to a housing of an apparatus in the area of a housing lead-through of the housing and is designed to have a comparatively low flexibility relative to the second grommet portion. The second grommet portion extends from the first grommet portion up to the free end of the cable grommet and is designed to have a comparatively high flexibility relative to the first grommet portion and is formed with grommet apertures in order to achieve the comparatively high flexibility, which grommet apertures are arranged after one another in a grommet direction which extends from the first grommet portion to the second grommet portion.
An apparatus of the type defined in the first paragraph and a grommet of the type defined in the second paragraph are known from the document DE 298 16 617 U1. In the known construction all the grommet apertures have the same aperture dimensions. When the known grommet is bent, as happens during use of the apparatus and in the case that the mains cord which is led through the grommet is wound around the housing of the apparatus, this results in a non-uniform bending in the second grommet portion, namely in such a manner that the radius of curvature increases comparatively strongly towards the free end of the grommet. As a result of this, the mains cord which is led through the grommet can be bent comparatively sharply in the area where it leaves the grommet, i.e. in the area of the free end of the grommet, which may comparatively soon lead to damage to the wires, the wire insulation and the cable sleeve of the mains cable.
It is an object of the invention to preclude the problems described hereinbefore and to provide an improved apparatus and an improved cable grommet.
According to the invention, in order to achieve the afore-mentioned object with an apparatus of the type defined in the first paragraph, the grommet apertures have at least one aperture dimension which increases in the grommet direction.
According to the invention, in order to achieve the afore-mentioned object with a cable grommet of the type defined in the second paragraph, the grommet apertures have at least one aperture dimension which increases in the grommet direction.
As a result of the provision of the measures in accordance with the invention, it is achieved, in a particularly simple manner and without any additional cost, because the formation of through-holes in accordance with the invention does not require any additional costs at all in comparison with the formation of through-holes in known manner, that during bending of the cable grommet in accordance with the invention a uniform bending occurs in the second grommet portion, i.e. a substantially constant radius of curvature is obtained in the second grommet portion, which precludes an excessive bending of the mains cable led through the cable grommet in the area of the free end of the cable grommet and consequently precludes adverse effects that may be caused by such excessive bending.
In an apparatus in accordance with the invention and in a cable grommet in accordance with the invention, grommet apertures of rectangular cross-sectional shape may be provided, which grommet apertures may have aperture dimensions in the grommet direction which, for example, increase parallel to the grommet direction. Alternatively, the aperture dimensions transverse to the grommet direction may also increase in the grommet direction. It has proved to be very advantageous when the grommet apertures have an increasing aperture cross-section, i.e. the aperture dimension increases both in a direction parallel to the grommet direction and in a direction transverse to the grommet direction.
In an apparatus in accordance with the invention and a cable grommet in accordance with the invention having grommet apertures of increasing aperture cross-sections, it has proved to be particularly advantageous when, in addition, the one or more of the following features are included: (a) the cable grommet has a substantially oval cross-sectional shape, and the grommet apertures are arranged in the four transitional portions between the longitudinal portions and the two apex portions of the substantially oval cross-sectional shape; (b) the grommet apertures have a funnel-like cross-sectional shape; (c) the grommet apertures are each bounded by a bounding wall which extends substantially parallel to the longitudinal portions and a second bounding wall which extends substantially perpendicularly to the longitudinal portions. Tests have shown that these embodiments are particularly advantageous.
The afore-mentioned as well as further aspects of the invention will be apparent from the example of an embodiment described hereinafter and will be elucidated with the aid of this example.